Not a stupid question at all. And the good news is YES! you can
use a lapidary type rotary tumbler for steel shot. The question
now becomes how much shot and water do I use and what kind of
burnishing soap if any.
Basically tumbling is composed of three elements: the media (in
this case shot), the burnishing compound (soap) and water
mixtures, and the tumbler itself.
There are a variety of shapes of shot to choose from. Since you
will be running silver jewelry pieces, the best thing to do is
get a mixture of shapes that will handle most jewelry geometries.
To save you the headache, we have a mixture specially designed
for Rotary Tumblers. I don’t know the size of your tumbler but I
suspect its one of the small Thumler’s Tumblers? If so, you can
buy the small 10 lb. container of shot and that will be plenty.
There are two kinds of shot: carbon steel shot and stainless
steel shot. Both kinds are available as premixed assorted
shapes. But the carbon is usually half the price of the
Carbon shot can rust so it’s important to use a burnishing
compound that has a rust preventative in it ~and~ to use plenty
of it. Once carbon shot is badly rusted it is next to impossible
to bring back. We suggest keeping a gallon of ‘Carbon Steel Shot
Cleaner’ on hand at all times in case of emergency. The minute
the shot looks grey or dull you can run it in the cleaner and
save it. (Instructions are on the bottle.)
If you choose Carbon Shot, you have to take a couple of things
into consideration when deciding what burnishing compound to use.
If you are using a rubber or rubber lined barrel, you can’t use
too aggressive a soap or it will degrade the rubber and make a
lovely grey/black mess of your shot and jewelry. For rubber
lined barrels I recommend our Burnishing Soap B (of course you
can ask other suppliers what they’d recommend as well).
If the barrel is plastic, use Burnishing Soap 70L. It’s very
aggressive and just great for carbon steel shot and won’t harm a
plastic barrel. DON’T use 70L with rubber barrels.
Stainless Steel Shot won’t rust so you can use any burnishing
compound designed for stainless steel shot, a good one is our
#44S. Stainless Steel Shot does have a tendency to turn grey
every once in a while. And grey dull shot produces, you guessed
it, grey dull jewelry. You can clean Stainless Steel Shot by
running it in your tumbler for 1/2 hour with a mixture of 50%
Coca-Cola and 50% water. Pepsi doesn’t work so well - I don’t
know why and yes I’m serious. After 1/2 hour, empty out the
coke/water mixture and check the shot. Depending on how bad it
was, you may or may not have to repeat the 1/2 hour clean-up run
another time or even several more times.
The actual burnishing of your jewelry is too easy! Fill the
tumbler barrel 50%-60% full with shot. Add enough cool water to
cover the level of the shot by about 1" to 2". Add burnishing
compound in the amount specified on the label. If you’re using
Carbon Steel Shot, add a little extra (won’t hurt and definitely
will help prevent rust).
Put your jewelry in. The ratio of shot to jewelry is about 5 to
1 by volume. That’s lower than most other other types of tumbling
because a rotary tumbler with shot really rolls the pieces rather
than shakes them - so you can get more in without worrying about
them scratching each other. So by way of example, lets say I was
running dimes. In one cup of shot I could put maybe 50 dimes
easy, but if i was running silver dollars, then maybe only 20.
I’m guesstimating since I’ve never run either but the bigger the
piece, the less you should put in. “When in doubt, better to run
too few than too many” is a good rule of thumb.
The amount of time the pieces run depends on their condition
before they went in. Pieces that had parting lines sanded off
and sprues removed and sanded and pits and bumps removed, will
come out best. Remember steel shot tumbling only burnishes the
pieces. If they go in dull with parting lines, they come out
shiny with parting lines.
So if parts are well prepared, 4-5 hours is usually good. But I
know plenty of people who run them much longer, even overnite. I
don’t particularly like leaving tumblers on overnite. If
something goes wrong - well there’s no one around to stop it.
So ok, I guess I’ve rambled on long enough. Sorry for the long
windedness. I actually DO have a life - but I’m home sick and
it’s Saturday nite and here I sit sniffling and feeling sorry for
Anyway I hope it helped a little. And if you have any
questions, please feel free to call me Monday at work.
Have I mentioned we have a free catalog?
GESSWEIN CO. INC. USA
Bridgeport CT 06605
Tech Support: 1-800-544-2043 (ext 287 for me)
24 Hr. Fax: 203-335-0300
(Or just email me here anytime - this is my personal acct.)